Optical imaging system

ABSTRACT

An optical imaging system includes a first lens, a second lens, a third lens, a fourth lens, a fifth lens, a sixth lens, and a seventh lens sequentially disposed in ascending numerical order along an optical axis of the optical imaging system from an object side of the optical imaging system toward an imaging surface of an image sensor, wherein a conditional expression f/f2+f/f3&lt;−0.4 is satisfied, where f is a focal length of the optical imaging system, f2 is a focal length of the second lens, and f3 is a focal length of the third lens, and a conditional expression TTL/(2*IMG HT)&lt;0.69 is satisfied, where TTL is a distance along the optical axis from an object-side surface of the first lens to the imaging surface of the image sensor, and IMG HT is one-half of a diagonal length of the imaging surface of the image sensor.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of application Ser. No. 16/778,496filed on Jan. 31, 2020, now U.S. Pat. No. 11,644,642 issued on May 9,2023, and claims the benefit under 35 USC 119(a) of Korean PatentApplication Nos. 10-2019-0020453 filed on Feb. 21, 2019, and10-2019-0091493 filed on Jul. 29, 2019, in the Korean IntellectualProperty Office, the entire disclosures of which are incorporated hereinby reference for all purposes.

BACKGROUND 1. Field

This application relates to an optical imaging system.

2. Description of Related Art

Recently, a portable terminal device has been designed to include acamera to allow a video call to be made and an image to be captured.Also, as a function of a camera in a portable terminal device isfrequently used, there has been an increased demand for a highresolution and a high performance in a camera of a portable terminaldevice.

However, as a size and a weight of a portable terminal has been reduced,there have been difficulties in implementing a camera having a highresolution and a high performance.

To address the above-described issue, a lens of a camera has beenmanufactured using a plastic material lighter than glass, and an opticalimaging system has been designed to include five or six lenses toimplement a high resolution.

SUMMARY

This Summary is provided to introduce a selection of concepts in asimplified form that are further described below in the DetailedDescription. This Summary is not intended to identify key features oressential features of the claimed subject matter, nor is it intended tobe used as an aid in determining the scope of the claimed subjectmatter.

In one general aspect, an optical imaging system includes a first lens,a second lens, a third lens, a fourth lens, a fifth lens, a sixth lens,and a seventh lens sequentially disposed in ascending numerical orderalong an optical axis of the optical imaging system from an object sideof the optical imaging system toward an imaging surface of an imagesensor, wherein a conditional expression f/f2+f/f3<−0.4 may besatisfied, where f is a focal length of the optical imaging system, f2is a focal length of the second lens, and f3 is a focal length of thethird lens, and a conditional expression TTL/(2*IMG HT)<0.69 may besatisfied, where TTL is a distance along the optical axis from anobject-side surface of the first lens to the imaging surface of theimage sensor, and IMG HT is one-half of a diagonal length of the imagingsurface of the image sensor.

A conditional expression n2+n3>3.15 may be satisfied, where n2 is arefractive index of the second lens, and n3 a refractive index of thethird lens.

A conditional expression n2+n3+n4>4.85 may be satisfied, where n4 is arefractive index of the fourth lens.

A conditional expression v1-v2>30 may be satisfied, where v1 is an Abbenumber of the first lens, and v2 is an Abbe number of the second lens.

A conditional expression 1.0<TTL/f<1.10 may be satisfied.

A conditional expression 0.15<BFL/f<0.25 may be satisfied, where BFL isa distance along the optical axis from an image-side surface of theseventh lens to the imaging surface of the image sensor.

A conditional expression 0.005<D1/f<0.04 may be satisfied, where D1 is adistance along the optical axis between an image-side surface of thefirst lens and an object-side surface of the second lens.

A conditional expression 0.30<R1/f<0.40 may be satisfied, where R1 is aradius of curvature of an object-side surface of the first lens.

A conditional expression 1.4<1f231/f1<2.8 may be satisfied, where f1 isa focal length of the first lens, and f23 is a composite focal length ofthe second lens and the third lens.

A conditional expression Fno<2.3 may be satisfied, where Fno is anF-number of the optical imaging system.

A refractive index of each of at least two lenses of the first toseventh lenses may be 1.67 or higher.

The first lens may have a positive refractive power, either one or bothof the second lens and the third lens may have a negative refractivepower, and a refractive index of each of the either one or both of thesecond lens and the third lens may be 1.67 or higher.

The first lens may have a positive refractive power, and the seventhlens may have a negative refractive power.

In another general aspect an optical imaging system includes a firstlens, a second lens, a third lens, a fourth lens, a fifth lens, a sixthlens, and a seventh lens sequentially disposed in ascending numericalorder along an optical axis of the optical imaging system from an objectside of the optical imaging system toward an imaging surface of an imagesensor, wherein the first lens has a positive refractive power, andeither one or both of the second lens and the third lens has a negativerefractive power, a conditional expression n2+n3>3.15 is satisfied,where n2 is a refractive index of the second lens, and n3 is arefractive index of the third lens, and a conditional expressionTTL/(2*IMG HT)<0.69 is satisfied, where TTL is a distance along theoptical axis from an object-side surface of the first lens to theimaging surface of the image sensor, and IMG HT is one-half of adiagonal length of the imaging surface of the image sensor.

A conditional expression f/f2+f/f3<−0.4 may be satisfied, where f is afocal length of the optical imaging system, f2 is a focal length of thesecond lens, and f3 is a focal length of the third lens.

A conditional expression v1-v2>30 and n2+n3+n4>4.85 may be satisfied,where v1 is an Abbe number of the first lens, v2 is an Abbe number ofthe second lens, and n4 is a refractive index of the fourth lens.

Other features and aspects will be apparent from the following detaileddescription, the drawings, and the claims.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a diagram illustrating a first example of an optical imagingsystem.

FIG. 2 is a diagram illustrating aberration properties of the opticalimaging system illustrated in FIG. 1 .

FIG. 3 is a diagram illustrating a second example of an optical imagingsystem.

FIG. 4 is a diagram illustrating aberration properties of the opticalimaging system illustrated in FIG. 3 .

FIG. 5 is a diagram illustrating a third example of an optical imagingsystem.

FIG. 6 is a diagram illustrating aberration properties of the opticalimaging system illustrated in FIG. 5 .

FIG. 7 is a diagram illustrating a fourth example of an optical imagingsystem.

FIG. 8 is a diagram illustrating aberration properties of the opticalimaging system illustrated in FIG. 7 .

FIG. 9 is a diagram illustrating a fifth example of an optical imagingsystem.

FIG. 10 is a diagram illustrating aberration properties of the opticalimaging system illustrated in 9.

Throughout the drawings and the detailed description, the same referencenumerals refer to the same elements. The drawings may not be to scale,and the relative size, proportions, and depiction of elements in thedrawings may be exaggerated for clarity, illustration, and convenience.

DETAILED DESCRIPTION

The following detailed description is provided to assist the reader ingaining a comprehensive understanding of the methods, apparatuses,and/or systems described herein. However, various changes,modifications, and equivalents of the methods, apparatuses, and/orsystems described herein will be apparent after an understanding of thedisclosure of this application. For example, the sequences of operationsdescribed herein are merely examples, and are not limited to those setforth herein, but may be changed as will be apparent after anunderstanding of the disclosure of this application, with the exceptionof operations necessarily occurring in a certain order. Also,descriptions of features that are known in the art may be omitted forincreased clarity and conciseness.

The features described herein may be embodied in different forms, andare not to be construed as being limited to the examples describedherein. Rather, the examples described herein have been provided merelyto illustrate some of the many possible ways of implementing themethods, apparatuses, and/or systems described herein that will beapparent after an understanding of the disclosure of this application.

The terminology used herein is for describing various examples only, andis not to be used to limit the disclosure. The articles “a,” “an,” and“the” are intended to include the plural forms as well, unless thecontext clearly indicates otherwise. The terms “comprises,” “includes,”and “has” specify the presence of stated features, numbers, operations,members, elements, and/or combinations thereof, but do not preclude thepresence or addition of one or more other features, numbers, operations,members, elements, and/or combinations thereof.

In the drawings, a thickness, a size, and a shape of each lens of anoptical imaging system may be exaggerated for ease of illustration, anda spherical or aspherical shape illustrated in the drawings is merely anexample, and the shape is not limited thereto.

A first lens of the optical imaging system is a lens that is closest toan object side of the optical imaging system, and a seventh lens of theoptical imaging system is a lens that is closest to an image sensor ofthe optical imaging system.

A first surface (or an object-side surface) of a lens is a surface thatfaces toward the object side of the optical imaging system, and a secondsurface (or an image-side surface) of a lens is a surface that facestoward the image sensor.

Numerical values of radiuses of curvature of surfaces of elements,thicknesses of elements, distances between elements, distances between asurface of one element and a surface of another element, focal lengths,and image heights (IMG HT) are expressed in millimeters (mm), and fieldsof view (FOV) are expressed in degrees. The thicknesses and thedistances are measured along the optical axis of the optical imagingsystem.

A statement that a surface of lens is convex means that at least aparaxial region of the surface is convex, a statement that a surface ofa lens is concave means that at least a paraxial region of the surfaceis concave, and a statement that a surface of a lens is planar meansthat at least a paraxial region of the surface is planar. Thus, evenwhen a surface of a lens is described as being convex, an edge region ofthe surface may be concave. Also, even when a surface of a lens isdescribed as being concave, an edge region of the surface may be convex.Also, even when a surface of a lens is described as being planar, anedge region of the surface may be convex or concave.

A paraxial region of a lens surface is a central portion of the lenssurface surrounding the optical axis of the lens surface in which lightrays incident to the lens surface make a small angle θ to the opticalaxis and the approximations sin θ≈θ, tan θ≈θ, and cos θ≈1 are valid.

The optical imaging system may include seven lenses.

For example, the optical imaging system may include a first lens, asecond lens, a third lens, a fourth lens, a fifth lens, a sixth lens,and a seventh lens disposed in ascending numerical order along anoptical axis of the optical imaging system from an object side of theoptical imaging system toward an image side of the optical imagingsystem. The first to seventh lenses may be disposed with predetermineddistances therebetween along the optical axis.

However, the optical imaging system may include other elements inaddition to the seven lenses.

For example, the optical imaging system may further include an imagesensor for converting an incident image of an object into an electricalsignal.

Also, the optical imaging system may further include an infrared filter(hereinafter referred to as a “filter”) for blocking infrared rays. Thefilter may be disposed between the seventh lens and the image sensor.

Also, an optical imaging system may further include a stop for adjustingan amount of light incident onto the image sensor. The stop may disposedat any desired position.

The first to seventh lenses included in the optical imaging system maybe made of a plastic material.

Any one or any combination of any two or more of the first to seventhlenses may have an aspherical surface. Alternatively, each of the firstto seventh lenses may have at least one aspherical surface.

Either one or both of a first surface and a second surface of each ofthe first to seventh lenses may be an aspherical surface defined byEquation 1 below.

$\begin{matrix}{Z = {\frac{{cY}^{2}}{1 + \sqrt{1 - {\left( {1 + K} \right)c^{2}Y^{2}}}} + {AY}^{4} + {BY^{6}} + {CY}^{8} + {Dy^{10}} + {EY^{12}} + {FY^{14}} + {GY}^{16} + {HY}^{18} + {{JY}^{20}\mspace{14mu}\ldots}}} & (1)\end{matrix}$

In Equation 1, “c” is a curvature of the aspherical surface at anoptical axis of the aspherical surface and is equal to an inverse of aradius of curvature of the aspherical surface at the optical axis, “K”is a conic constant, “Y” is a distance from a random point on theaspherical surface to the optical axis in a direction perpendicular tothe optical axis, “A” to “H” and “J” are aspherical coefficients of theaspherical surface, and “Z” is a distance from the random point on theaspherical surface to a plane perpendicular to the optical axis andcontaining an apex of the aspherical surface in a direction parallel tothe optical axis.

In one example, the first to seventh lenses respectively may have apositive refractive power, a negative refractive power, a positiverefractive power, a positive refractive power, a positive refractivepower, a positive refractive power, and a negative refractive power.

In another example, the first to seventh lenses respectively may have apositive refractive power, a positive refractive power, a negativerefractive power, a positive refractive power, a positive refractivepower, a positive refractive power, and a negative refractive power.

In another example, the first to seventh lenses respectively may have apositive refractive power, a negative refractive power, a negativerefractive power, a positive refractive power, a positive refractivepower, a positive refractive power, and a negative refractive power.

In another example, the first to seventh lenses respectively may have apositive refractive power, a negative refractive power, a negativerefractive power, a positive refractive power, a positive refractivepower, a negative refractive power, and a negative refractive power.

In another example, the first to seventh lenses respectively may have apositive refractive power, a negative refractive power, a positiverefractive power, a negative refractive power, a negative refractivepower, a positive refractive power, and a negative refractive power.

Examples of the optical imaging system may satisfy any one or anycombination of any two or more of Conditional Expressions 1 to 11 below.f/f2+f/f3<−0.4  (Conditional Expression 1)v1-v2>30  (Conditional Expression 2)1.0<TTL/f<1.10  (Conditional Expression 3)n2+n3>3.15  (Conditional Expression 4)0.15<BFL/f<0.25  (Conditional Expression 5)0.005<D1/f<0.04  (Conditional Expression 6)0.30<R1/f<0.40  (Conditional Expression 7)TTL/(2*IMG HT)<0.69  (Conditional Expression 8)Fno<2.3  (Conditional Expression 9)n2+n3+n4>4.85  (Conditional Expression 10)1.4<|f23|/f1<2.8  (Conditional Expression 11)

In Conditional Expressions 1 to 11, “f” is a focal length of the opticalimaging system, “f1” is a focal length of the first lens, “f2” is afocal length of the second lens, “f3” is a focal length of the thirdlens, “f23” is a composite focal length of the second lens and the thirdlens, “v1” is an Abbe number of the first lens, “v2” is an Abbe numberof the second lens, “TTL” is a distance along an optical axis of theoptical imaging system from an object-side surface of the first lens toan imaging surface of an image sensor, “n2” is a refractive index of thesecond lens, “n3” is a refractive index of the third lens, “n4” is arefractive index of the fourth lens, “BFL” is a distance along theoptical axis from an image-side surface of the seventh lens to theimaging surface of the image sensor, “D1” is a distance along theoptical axis between an image-side surface of the first lens and anobject-side surface of the second lens, “R1” is a radius of curvature ofan object-side surface of the first lens, “IMG HT” is one-half of adiagonal length of the imaging surface of the image sensor, and “Fno” isan F-number of the optical imaging system.

In the description below, the first to seventh lenses in examples of theoptical imaging system will be described.

The first lens may have a positive refractive power. The first lens mayhave a meniscus shape that is convex towards an object side of theoptical imaging system. In other words, a first surface of the firstlens may be convex, and a second surface of the first lens may beconcave.

Either one or both of the first surface and the second surface of thefirst lens may be aspherical. For example, both surfaces of the firstlens may be aspherical.

The second lens may have a positive refractive power or a negativerefractive power. The second lens may have a meniscus shape that isconvex towards the object side of the optical imaging system. In otherwords, a first surface of the second lens may be convex, and a secondsurface of the second lens may be concave.

Either one or both of the first surface and the second surface of thesecond lens may be aspherical. For example, both surfaces of the secondlens may be aspherical.

The third lens may have a positive refractive power or a negativerefractive power. The third lens may have a meniscus shape that isconvex towards the object side of the optical imaging system. In otherwords, a first surface of the third lens may be convex, and a secondsurface of the third lens may be concave.

Either one or both of the first surface and the second surface of thethird lens may be aspherical. For example, both surfaces of the thirdlens may be aspherical.

At least one inflection point may be formed on either one or both of thefirst surface and the second surface of the third lens. For example, thefirst surface of the third lens may be convex in a paraxial region ofthe first surface, and may be concave in an edge region of the firstsurface.

The fourth lens may have a positive refractive power or a negativerefractive power. The fourth lens may have a meniscus shape that isconvex towards the object side of the optical imaging system. In otherwords, a first surface of the fourth lens may be convex, and a secondsurface of the fourth lens may be concave.

Alternatively, the first surface of the fourth lens may be planar in aparaxial region of the first surface, and the second surface may beconvex.

Alternatively, both surfaces of the fourth lens may be convex. In otherwords, the first surface and the second surface of the fourth lens maybe convex.

Either one or both of the first surface and the second surface of thefourth lens may be aspherical. For example, both surfaces of the fourthlens may be aspherical.

At least one inflection point may be formed on either one or both of thefirst surface and the second surface of the fourth lens. For example,the second surface of the fourth lens may be concave in a paraxialregion of the second surface, and may be convex in an edge region of thesecond surface.

The fifth lens may have a positive refractive power or a negativerefractive power. The fifth lens may have a meniscus shape that isconvex towards the object side of the optical imaging system. In otherwords, a first surface of the fifth lens may be convex in a paraxialregion of the first surface, and a second surface of the fifth lens maybe concave.

Alternatively, both surfaces of the fifth lens may be convex. In otherwords, the first surface and the second surface of the fifth lens may beconvex.

Alternatively, both surfaces of the fifth lens may be concave. In otherwords, the first surface and the second surface of the fifth lens may beconcave.

Either one or both of the first surface and the second surface of thefifth lens may be aspherical. For example, both surfaces of the fifthlens may be aspherical.

At least one inflection point may be formed on either one or both of thefirst surface and the second surface of the fifth lens. For example, thefirst surface of the fifth lens may be convex in a paraxial region ofthe first surface, and may be concave in an edge region of the firstsurface. The second surface of the fifth lens may be concave in aparaxial region of the second surface, and may be convex in an edgeregion of the second surface.

The sixth lens may have a positive refractive power or a negativerefractive power. Both surfaces of the sixth lens may be convex. Inother words, a first surface and a second surface of the sixth lens maybe convex in a paraxial region of the second surface.

The sixth lens may have a meniscus shape that is convex towards an imageside of the optical imaging system. In other words, the first surface ofthe sixth lens may be concave in a paraxial region of the first surface,and the second surface of the sixth lens may be convex in a paraxialregion of the second surface.

Alternatively, the sixth lens may have a meniscus shape that is convextowards the object side of the optical imaging system. In other words,the first surface of the sixth lens may be convex in a paraxial regionof the first surface, and the second surface of the sixth lens may beconcave in a paraxial region of the first surface.

Either one or both of the first surface and the second surface of thesixth lens may be aspherical. For example, both surfaces of the sixthlens may be aspherical.

At least one inflection point may be formed on either one or both of thefirst surface and the second surface of the sixth lens. For example, thefirst surface of the sixth lens may be convex in a paraxial region ofthe first surface, and may be concave in an edge region of the firstsurface. The second surface of the sixth lens may be convex in aparaxial region of the second surface, and may be concave in an edgeregion of the second surface.

The seventh lens may have a negative refractive power. Both surfaces ofthe seventh lens may be concave. In other words, a first surface of theseventh lens may be concave in a paraxial region of the first surface,and a second surface of the seventh lens may be concave in a paraxialregion of the second surface.

Alternatively, the seventh lens may have a meniscus shape that is convextowards the object side of the optical imaging system. In other words,the first surface of the seventh lens may be convex in the paraxialregion of the first surface, and the second surface of the seventh lensmay be concave in the paraxial region of the second surface.

Either one or both of the first surface and the second surface of theseventh lens may be aspherical. For example, both surfaces of theseventh lens may be aspherical.

At least one inflection point may be formed on either one or both of thefirst surface and the second surface of the seventh lens. For example,the first surface of the seventh lens may be concave in the paraxialregion of the first surface, and may be convex in an edge region of thefirst surface. The second surface of the seventh lens may be concave inthe paraxial region of the second surface, and may be convex in an edgeregion of the second surface.

The first lens may be made of a first plastic material, and the secondlens may be made of a second plastic material having optical propertiesthat are different from optical properties of the first plasticmaterial.

A refractive index of at least one of the first to seventh lenses may be1.67 or higher.

Also, a refractive index of each of at least two lenses of the first toseventh lenses may be 1.67 or higher. For example, in one example, arefractive index of each of three lenses of the first to seventh lensesmay be 1.67 or higher, and in another example, a refractive index ofeach of two lenses of the first to seventh lenses may be 1.67 or higher.

A refractive index of a lens having a negative refractive power amongthe first to third lenses may be 1.67 or higher. As an example, eitherone or both of the second lens and the third lens may have a negativerefractive power, and may have a refractive index of 1.67 or higher.

Examples of an optical imaging system having first to seventh lensesconfigured as described above have improved aberration properties.

FIG. 1 is a diagram illustrating a first example of an optical imagingsystem, and FIG. 2 is a diagram illustrating aberration properties ofthe optical imaging system illustrated in FIG. 1 .

The optical imaging system of the first example may include a first lens110, a second lens 120, a third lens 130, a fourth lens 140, a fifthlens 150, a sixth lens 160, and a seventh lens 170, and may furtherinclude a stop (not shown), a filter 180, and an image sensor 190.

Characteristics of elements illustrated in FIG. 1 , including radiusesof curvature of surfaces of elements, thicknesses of elements, distancesbetween elements, refractive indexes of elements, Abbe numbers ofelements, and focal lengths of elements, are listed in Table 1 below.

TABLE 1 Sur- Thick- Refrac- Abbe face Radius of ness or tive Num- FocalNo. Element Curvature Distance Index ber Length S1 First 2.136 0.9941.549 63.6 5.320 S2 Lens 6.556 0.182 S3 Second 6.634 0.277 1.680 19.2−12.9434 S4 Lens 3.718 0.299 S5 Third 8.306 0.203 1.680 19.2 662.426 S6Lens 8.379 0.234 S7 Fourth 5.127 0.216 1.546 56.1 355.9385 S8 Lens 5.1870.362 S9 Fifth 2.777 0.248 1.680 19.2 148.2741 S10 Lens 2.753 0.564 S11Sixth 5.361 0.404 1.546 56.1 5.881274 S12 Lens −7.813 0.967 S13 Seventh−2.867 0.342 1.568 63.4 −3.76588 S14 Lens 8.893 0.125 S15 FilterInfinity 0.110 1.518 64.2 S16 Infinity 0.684 S17 Imaging Infinity −0.010Surface

In the first example, a focal length f of the optical imaging system is5.744 mm, Fno is 2.01, FOV is 77.23°, BFL is 0.909 mm, TTL is 6.201 mm,and IMG HT is 4.56 mm.

Fno is a number indicating a brightness of the optical imaging system,and is equal to the effective focal length of the optical imaging systemdivided by the entrance pupil diameter of the optical imaging system,FOV is a field of view of the optical imaging system, BFL is a distancealong an optical axis of the optical imaging system from an image-sidesurface of the seventh lens to an imaging surface of the image sensor,TTL is a distance along the optical axis from an object-side surface ofthe first lens to the imaging surface of the image sensor, and IMG HT isone-half of a diagonal length of the imaging surface of the imagesensor.

In the first example, the first lens 110 may have a positive refractivepower, a first surface of the first lens 110 may be convex, and a secondsurface of the first lens 110 may be concave.

The second lens 120 may have a negative refractive power, a firstsurface of the second lens 120 may be convex, and a second surface ofthe second lens 120 may be concave.

The third lens 130 may have a positive refractive power, a first surfaceof the third lens 130 may be convex in a paraxial region of the firstsurface, and a second surface of the third lens 130 may be concave in aparaxial region of the second surface.

At least one inflection point may be formed on either one or both of thefirst surface and the second surface of the third lens 130. For example,the first surface of the third lens 130 may be convex in a paraxialregion of the first surface, and may be concave in an edge region of thefirst surface. The second surface of the third lens 130 may be concavein a paraxial region of the second surface, and may be convex in an edgeregion of the second surface.

The fourth lens 140 may have a positive refractive power, a firstsurface of the fourth lens 140 may be convex, and a second surface ofthe fourth lens 140 may be concave.

The fifth lens 150 may have a positive refractive power, a first surfaceof the fifth lens 150 may be convex in a paraxial region of the firstsurface, and a second surface of the fifth lens 150 may be concave in aparaxial region of the second surface.

At least one inflection point may be formed on either one or both of thefirst surface and the second surface of the fifth lens 150. For example,the first surface of the fifth lens 150 may be convex in a paraxialregion of the first surface, and may be concave in an edge region of thefirst surface. The second surface of the fifth lens 150 may be concavein a paraxial region of the second surface, and may be convex in an edgeregion of the second surface.

The sixth lens 160 may have a positive refractive power, and the firstsurface and the second surface of the sixth lens 160 may be convex.

At least one inflection point may be formed on either one or both of thefirst surface and the second surface of the sixth lens 160. For example,the first surface of the sixth lens 160 may be convex in a paraxialregion of the first surface, and may be concave in an edge region of thefirst surface. The second surface of the sixth lens 160 may be convex ina paraxial region of the second surface, and may be concave in an edgeregion of the second surface.

The seventh lens 170 may have a negative refractive power, a firstsurface of the seventh lens 170 may be concave in a paraxial region ofthe first surface, and a second surface of the seventh lens 170 may beconcave in a paraxial region of the second surface.

At least one inflection point may be formed on either one or both of thefirst surface and the second surface of the seventh lens 170. Forexample, the first surface of the seventh lens 170 may be concave in aparaxial region of the first surface, and may be convex in an edgeregion of the first surface. The second surface of the seventh lens 170may be concave in a paraxial region of the second surface, and may beconvex in an edge region of the second surface.

The surfaces of the first lens 110 to the seventh lens 170 may have theaspheric coefficients listed in Table 2 below. For example, each of anobject-side surface and an image-side surface of each of the first lens110 to the seventh lens 170 may be aspherical.

TABLE 2 S1 S2 S3 S4 S5 S6 S7 K −1.391 −41.532 22.994 5.557 −96.881−27.470 −45.144 A 0.021 −0.033 −0.115 −0.081 −0.020 −0.015 0.056 B−0.031 −0.006 0.200 0.108 −0.234 −0.193 −0.161 C 0.080 0.134 −0.380−0.066 0.906 0.472 0.189 D −0.120 −0.363 0.740 0.059 −2.271 −0.702−0.120 E 0.111 0.543 −1.022 −0.038 3.836 0.712 0.042 F −0.064 −0.4920.902 −0.062 −4.262 −0.514 −0.007 G 0.022 0.266 −0.486 0.139 2.936 0.2510.000 H −0.004 −0.079 0.146 −0.094 −1.131 −0.072 0.000 J 0.000 0.010−0.019 0.023 0.186 0.009 0.000 S8 S9 S10 S11 S12 S13 S14 K −68.094−24.568 −23.418 −37.555 3.848 −4.196 −0.624 A 0.033 −0.022 −0.042 0.0270.049 −0.066 −0.075 B −0.080 −0.034 −0.022 −0.038 −0.028 0.036 0.036 C0.058 0.070 0.057 0.022 0.011 −0.012 −0.013 D −0.009 −0.068 −0.051−0.008 −0.002 0.003 0.003 E −0.010 0.038 0.025 0.002 0.000 0.000 −0.001F 0.007 −0.013 −0.008 0.000 0.000 0.000 0.000 G −0.002 0.003 0.001 0.0000.000 0.000 0.000 H 0.000 0.000 0.000 0.000 0.000 0.000 0.000 J 0.0000.000 0.000 0.000 0.000 0.000 0.000

The first example of the optical imaging system illustrated in FIG. 1configured according to Tables 1 and 2 above may have the aberrationproperties illustrated in FIG. 2 .

FIG. 3 is a diagram illustrating a second example of an optical imagingsystem, and FIG. 4 is a diagram illustrating aberration properties ofthe optical imaging system illustrated in FIG. 3 .

The optical imaging system of the second example may include a firstlens 210, a second lens 220, a third lens 230, a fourth lens 240, afifth lens 250, a sixth lens 260, and a seventh lens 270 and may furtherinclude a stop (not shown), a filter 280, and an image sensor 290.

Characteristics of elements illustrated in FIG. 3 , including radiusesof curvature of surfaces of elements, thicknesses of elements, distancesbetween elements, refractive indexes of elements, Abbe numbers ofelements, and focal lengths of elements, are listed in Table 3 below.

TABLE 3 Sur- Thick- Refrac- Abbe face Radius of ness or tive Num- FocalNo. Element Curvature Distance Index ber Length S1 First 1.962 0.6711.546 56.1 5.441 S2 Lens 5.069 0.061 S3 Second 6.492 0.248 1.621 25.820.74802 S4 Lens 12.891 0.121 S5 Third 11.498 0.192 1.689 18.4 −7.739 S6Lens 3.618 0.515 S7 Fourth 11.863 0.272 1.680 19.2 92.57202 S8 Lens14.484 0.400 S9 Fifth 2.887 0.240 1.680 19.2 70.44759 S10 Lens 2.9690.636 S11 Sixth 6.393 0.321 1.546 56.1 8.557163 S12 Lens −17.109 1.297S13 Seventh −2.593 0.320 1.546 56.1 −4.43142 S14 Lens 38.197 0.125 S15Filter Infinity 0.110 1.518 64.2 S16 Infinity 0.690 S17 Imaging Infinity−0.018 Plane

In the second example, a focal length f of the optical imaging system is6.000 mm, Fno is 2.18, FOV is 72.96°, BFL is 0.908 mm, TTL is 6.202 mm,and IMG HT is 4.56 mm.

The definitions of Fno, FOV, BFL, TTL, and IMG HT are the same as in thefirst example.

In the second example, the first lens 210 may have a positive refractivepower, a first surface of the first lens 210 may be convex, and a secondsurface of the first lens 210 may be concave.

The second lens 220 may have a positive refractive power, a firstsurface of the second lens 220 may be convex, and a second surface ofthe second lens 220 may be concave.

The third lens 230 may have a negative refractive power, a first surfaceof the third lens 230 may be convex, and a second surface of the thirdlens 230 may be concave.

The fourth lens 240 may have a positive refractive power, a firstsurface of the fourth lens 240 may be convex in a paraxial region of thefirst surface, and a second surface of the fourth lens 240 may beconcave in a paraxial region of the second surface.

At least one inflection point may be formed on either one or both of thefirst surface and the second surface of the fourth lens 240. Forexample, the first surface of the fourth lens 240 may be convex in aparaxial region of the first surface, and may be concave in an edgeregion of the first surface. The second surface of the fourth lens 240may be concave in a paraxial region of the second surface, and may beconvex in an edge region of the second surface.

The fifth lens 250 may have a positive refractive power, a first surfaceof the fifth lens 250 may be convex in a paraxial region of the firstsurface, and a second surface of the fifth lens 250 may be concave in aparaxial region of the second surface.

At least one inflection point may be formed on either one or both of thefirst surface and the second surface of the fifth lens 250. For example,the first surface of the fifth lens 250 may be convex in a paraxialregion of the first surface, and may be concave in an edge region of thefirst surface. The second surface of the fifth lens 250 may be concavein a paraxial region of the second surface, and may be convex in an edgeregion of the second surface.

The sixth lens 260 may have a positive refractive power, a first surfaceof the sixth lens may be convex in a paraxial region of the firstsurface, and a second surface of the sixth lens 260 may be convex in aparaxial region of the second surface.

At least one inflection point may be formed on either one or both of thefirst surface and the second surface of the sixth lens 260. For example,the first surface of the sixth lens 260 may be convex in a paraxialregion of the first surface, and may be concave in an edge region of thefirst surface. The second surface of the sixth lens 260 may be convex ina paraxial region of the second surface and may be concave in an edgeregion of the second surface.

The seventh lens 270 may have a negative refractive power, a firstsurface of the seventh lens 270 may be concave in a paraxial region ofthe first surface, and a second surface of the seventh lens 270 may beconcave in a paraxial region of the second surface.

At least one inflection point may be formed on either one or both of thefirst surface and the second surface of the seventh lens 270. Forexample, the first surface of the seventh lens 270 may be concave in aparaxial region of the first surface, and may be convex in an edgeregion of the first surface. The second surface of the seventh lens 270may be concave in a paraxial region of the second surface, and may beconvex in an edge region of the second surface.

The surfaces of the first lens 210 to the seventh lens 270 may have theaspheric coefficients listed in Table 4 below. For example, each of anobject-side surface and an image-side surface of each of the first lens210 to the seventh lens 270 may be aspherical.

TABLE 4 S1 S2 S3 S4 S5 S6 S7 K −1.048 −21.819 16.835 11.583 −11.4655.970 −79.619 A 0.008 −0.106 −0.153 −0.038 −0.002 −0.025 −0.026 B 0.0270.119 0.268 0.185 0.004 0.129 −0.052 C −0.069 0.101 −0.170 −0.375 −0.163−0.706 0.227 D 0.114 −0.420 −0.109 0.431 0.390 1.852 −0.623 E −0.1160.537 0.295 −0.310 −0.415 −2.706 0.949 F 0.072 −0.371 −0.243 0.144 0.2402.377 −0.856 G −0.026 0.145 0.100 −0.042 −0.070 −1.238 0.457 H 0.005−0.030 −0.020 0.007 0.006 0.349 −0.132 J 0.000 0.003 0.002 −0.001 0.001−0.041 0.016 S8 S9 S10 S11 S12 S13 S14 K −99.000 −22.463 −24.850 −55.43843.550 −8.774 −99.000 A −0.057 −0.036 −0.039 0.027 0.039 −0.083 −0.050 B−0.002 −0.006 −0.018 −0.065 −0.041 0.034 0.015 C 0.094 0.037 0.056 0.0430.018 −0.008 −0.003 D −0.289 −0.038 −0.051 −0.023 −0.006 0.001 0.000 E0.394 0.016 0.024 0.009 0.002 0.000 0.000 F −0.302 −0.003 −0.006 −0.0020.000 0.000 0.000 G 0.134 0.000 0.001 0.000 0.000 0.000 0.000 H −0.0320.000 0.000 0.000 0.000 0.000 0.000 J 0.003 0.000 0.000 0.000 0.0000.000 0.000

The second example of the optical imaging system illustrated in FIG. 3configured according to Tables 3 and 4 above may have the aberrationproperties illustrated in FIG. 4 .

FIG. 5 is a diagram illustrating a third example of an optical imagingsystem, and FIG. 6 is a diagram illustrating aberration properties ofthe optical imaging system illustrated in FIG. 5 .

The optical imaging system of the third example may include a first lens310, a second lens 320, a third lens 330, a fourth lens 340, a fifthlens 350, a sixth lens 360, and a seventh lens 370 and may furtherinclude a stop, a filter 380, and an image sensor 390.

Characteristics of elements illustrated in FIG. 5 , including radiusesof curvature of surfaces of elements, thicknesses of elements, distancesbetween elements, refractive indexes of elements, Abbe numbers ofelements, and focal lengths of elements, are listed in Table 5 below.

TABLE 5 Sur- Thick- Refrac- Abbe face Radius of ness or tive Num- FocalNo. Element Curvature Distance Index ber Length S1 First 1.830 0.8061.546 56.1 3.972 S2 Lens 9.862 0.115 S3 Second 127.068 0.206 1.689 18.4−9.14824 S4 Lens 6.001 0.355 S5 Third 10.749 0.181 1.680 19.2 −39.200 S6Lens 7.606 0.322 S7 Fourth Infinity 0.516 1.669 20.4 17.46074 S8 Lens−11.676 0.701 S9 Fifth 77.052 0.361 1.546 56.1 18.8306 S10 Lens −11.8580.208 S11 Sixth −6.355 0.248 1.621 25.8 120.6967 S12 Lens −5.946 0.594S13 Seventh −35.464 0.354 1.546 56.1 −4.89062 S14 Lens 2.901 0.506 S15Filter Infinity 0.110 1.518 64.2 S16 Infinity 0.638 S17 Imaging Infinity−0.020 Plane

In the third example, a focal length f of the optical imaging system is6.000 mm, Fno is 2.14, FOV is 73.59°, BFL is 1.234 mm, TTL is 6.200 mm,and IMG HT is 4.56 mm.

The definitions of Fno, FOV, BFL, TTL, and IMG HT are the same as in thefirst example.

In the third example, the first lens 310 may have a positive refractivepower, a first surface of the first lens 310 may be convex, and a secondsurface of the first lens 310 may be concave.

The second lens 320 may have a negative refractive power, a firstsurface of the second lens 320 may be convex, and a second surface ofthe second lens 320 may be concave.

The third lens 330 may have a negative refractive power, a first surfaceof the third lens 330 may be convex in a paraxial region of the firstsurface, and a second surface of the third lens 330 may be concave in aparaxial region of the second surface.

At least one inflection point may be formed on either one or both of thefirst surface and the second surface of the third lens 330. For example,the first surface of the third lens 330 may be convex in a paraxialregion of the first surface, and may be concave in an edge region of thefirst surface. The second surface of the third lens 330 may be concavein a paraxial region of the second surface, and may be convex in an edgeregion of the second surface.

The fourth lens 340 may have a positive refractive power, a firstsurface of the fourth lens 340 may be planar in a paraxial region of thefirst surface, and a second surface of the fourth lens 340 may be convexin a paraxial region of the second surface.

At least one inflection point may be formed on either one or both of thefirst surface and the second surface of the fourth lens 340. Forexample, the first surface of the fourth lens 340 may be planar in aparaxial region of the first surface, and may be convex in an edgeregion of the first surface.

The fifth lens 350 may have a positive refractive power, and a firstsurface and a second surface of the fifth lens 350 may be convex.

The sixth lens 360 may have a positive refractive power, a first surfaceof the sixth lens 360 may be concave, and a second surface of the sixthlens 360 may be convex.

The seventh lens 370 may have a negative refractive power, a firstsurface of the seventh lens may be concave in a paraxial region of thefirst surface, and a second surface of the seventh lens 370 may beconcave in a paraxial region of the second surface.

At least one inflection point may be formed on either one or both of thefirst surface and the second surface of the seventh lens 370. Forexample, the first surface of the seventh lens 370 may be concave in aparaxial region of the first surface, and may be convex in an edgeregion of the first surface. The second surface of the seventh lens 370may be concave in a paraxial region of the second surface, and may beconvex in an edge region of the second surface.

The surfaces of the first lens 310 to the seventh lens 370 may have theaspheric coefficients listed in Table 6 below. For example, each of anobject-side surface and an image-side surface of each of the first lens310 to the seventh lens 370 may be aspherical.

TABLE 6 S1 S2 S3 S4 S5 S6 S7 K −0.841 26.507 15.248 6.857 0.000 0.000−95.502 A 0.019 −0.011 0.017 0.019 −0.123 −0.131 −0.064 B −0.008 0.0550.078 0.022 0.087 0.141 0.013 C 0.039 −0.131 −0.180 0.064 −0.056 −0.1740.014 D −0.072 0.195 0.288 −0.227 0.170 0.362 0.006 E 0.077 −0.185−0.292 0.378 −0.293 −0.467 −0.024 F −0.047 0.107 0.184 −0.332 0.2660.353 0.021 G 0.015 −0.034 −0.063 0.156 −0.124 −0.146 −0.008 H −0.0020.004 0.009 −0.030 0.023 0.025 0.001 J 0.000 0.000 0.000 0.000 0.0000.000 0.000 S8 S9 S10 S11 S12 S13 S14 K −1.463 83.726 19.055 6.205 3.30135.076 −0.120 A −0.054 −0.054 −0.081 −0.039 0.035 −0.109 −0.149 B 0.0010.043 0.164 0.115 −0.009 0.031 0.064 C 0.020 −0.072 −0.218 −0.168 −0.027−0.005 −0.026 D −0.037 0.050 0.154 0.112 0.022 0.001 0.008 E 0.042−0.018 −0.064 −0.043 −0.008 0.000 −0.002 F −0.026 0.002 0.016 0.0110.001 0.000 0.000 G 0.009 0.000 −0.002 −0.002 0.000 0.000 0.000 H −0.0010.000 0.000 0.000 0.000 0.000 0.000 J 0.000 0.000 0.000 0.000 0.0000.000 0.000

The third example of the optical imaging system illustrated in FIG. 5configured according to Tables 5 and 6 above may have the aberrationproperties illustrated in FIG. 6 .

FIG. 7 is a diagram illustrating a fourth example of an optical imagingsystem, and FIG. 8 is a diagram illustrating aberration properties ofthe optical imaging system illustrated in FIG. 7 .

The optical imaging system of the fourth example may include a firstlens 410, a second lens 420, a third lens 430, a fourth lens 440, afifth lens 450, a sixth lens 460, and a seventh lens 470 and may furtherinclude a stop, a filter 480, and an image sensor 490.

Characteristics of elements illustrated in FIG. 7 , including radiusesof curvature of surfaces of elements, thicknesses of elements, distancesbetween elements, refractive indexes of elements, Abbe numbers ofelements, and focal lengths of elements, are listed in Table 7 below.

TABLE 7 Sur- Thick- Refrac- Abbe face Radius of ness or tive Num- FocalNo. Element Curvature Distance Index ber Length S1 First 1.827 0.7681.546 56.1 3.998 S2 Lens 9.512 0.066 S3 Second 120.115 0.203 1.680 19.2−10.1838 S4 Lens 6.538 0.304 S5 Third 7.720 0.182 1.680 19.2 −20.076 S6Lens 4.883 0.380 S7 Fourth 30.302 0.506 1.669 20.4 14.26375 S8 Lens−13.826 0.701 S9 Fifth 44.211 0.340 1.546 56.1 16.67144 S10 Lens −11.4450.271 S11 Sixth −5.957 0.250 1.621 25.8 −290.909 S12 Lens −6.259 0.696S13 Seventh −36.032 0.335 1.546 56.1 −5.00505 S14 Lens 2.970 0.505 S15Filter Infinity 0.110 1.518 64.2 S16 Infinity 0.601 S17 Imaging Infinity−0.020 Plane

In the fourth example, a focal length f of the optical imaging system is6.000 mm, Fno is 2.20, FOV is 74.55°, BFL is 1.196 mm, TTL is 6.200 mm,and IMG HT is 4.56 mm.

The definitions of Fno, FOV, BFL, TTL, and IMG HT are the same as in thefirst example.

In the fourth example, the first lens 410 may have a positive refractivepower, a first surface of the first lens 410 may be convex, and a secondsurface of the first lens 410 may be concave.

The second lens 420 may have a negative refractive power, a firstsurface of the second lens 420 may be convex, and a second surface ofthe second lens 420 may be concave.

The third lens 430 may have a negative refractive power, a first surfaceof the third lens 430 may be convex in a paraxial region of the firstsurface, and a second surface of the third lens 430 may be concave.

At least one inflection point may be formed on either one or both of thefirst surface and the second surface of the third lens 430. For example,the first surface of the third lens 430 may be convex in a paraxialregion of the first surface, and may be concave in an edge region of thefirst surface.

The fourth lens 440 may have a positive refractive power, and a firstsurface and a second surface of the fourth lens 440 may be convex.

The fifth lens 450 may have a positive refractive power, and a firstsurface and a second surface of the fifth lens 450 may be convex.

The sixth lens 460 may have a negative refractive power, a first surfaceof the sixth lens 460 may be concave, and a second surface of the sixthlens 460 may be convex.

The seventh lens 470 may have a negative refractive power, a firstsurface of the seventh lens 470 may be concave in a paraxial region ofthe first surface, and a second surface of the seventh lens 470 may beconcave in a paraxial region of the second surface.

At least one inflection point may be formed on either one or both of thefirst surface and the second surface of the seventh lens 470. Forexample, the first surface of the seventh lens 470 may be concave in aparaxial region of the first surface, and may be convex in an edgeregion of the first surface. The second surface of the seventh lens 470may be concave in a paraxial region of the second surface, and may beconvex in an edge region of the second surface.

The surfaces of the first lens 410 to the seventh lens 470 may have theaspheric coefficients listed in Table 8 below. For example, each of anobject-side surface and an image-side surface of each of the first lens410 to the seventh lens 470 may be aspherical.

TABLE 8 S1 S2 S3 S4 S5 S6 S7 K −0.826 26.805 −99.000 6.347 0.000 0.000−95.502 A 0.010 −0.026 −0.004 −0.006 −0.144 −0.149 −0.057 B 0.053 0.0850.138 0.167 0.081 0.203 −0.002 C −0.164 −0.102 −0.160 −0.394 0.359−0.232 0.089 D 0.328 0.051 −0.002 0.809 −1.374 0.379 −0.191 E −0.4080.027 0.263 −1.276 2.653 −0.503 0.251 F 0.319 −0.081 −0.381 1.426 −3.0710.448 −0.205 G −0.152 0.071 0.270 −1.024 2.121 −0.249 0.101 H 0.040−0.028 −0.097 0.423 −0.802 0.078 −0.028 J −0.005 0.004 0.014 −0.0760.128 −0.011 0.003 S8 S9 S10 S11 S12 S13 S14 K −4.999 71.505 18.7485.407 3.770 −52.747 −0.156 A −0.064 −0.055 −0.067 −0.012 0.046 −0.082−0.122 B 0.065 0.028 0.106 0.042 −0.028 −0.001 0.035 C −0.172 −0.013−0.112 −0.070 −0.016 0.015 −0.008 D 0.305 −0.039 0.041 0.028 0.020−0.007 0.001 E −0.340 0.055 0.009 0.004 −0.008 0.002 0.000 F 0.241−0.033 −0.013 −0.007 0.002 0.000 0.000 G −0.105 0.010 0.005 0.002 0.0000.000 0.000 H 0.026 −0.002 −0.001 0.000 0.000 0.000 0.000 J −0.003 0.0000.000 0.000 0.000 0.000 0.000

The fourth example of the optical imaging system illustrated in FIG. 7configured according to Tables 7 and 8 above may have the aberrationproperties illustrated in FIG. 8 .

FIG. 9 is a diagram illustrating a fifth example of an optical imagingsystem, and FIG. 10 is a diagram illustrating aberration properties ofthe optical imaging system illustrated in FIG. 9 .

The optical imaging system of the fifth example may include a first lens510, a second lens 520, a third lens 530, a fourth lens 540, a fifthlens 550, a sixth lens 560, and a seventh lens 570 and may furtherinclude a stop, a filter 580, and an image sensor 590.

Characteristics of elements illustrated in FIG. 9 , including radiusesof curvature of surfaces of elements, thicknesses of elements, distancesbetween elements, refractive indexes of elements, Abbe numbers ofelements, and focal lengths of elements, are listed in Table 9 below.

TABLE 9 Sur- Thick- Refrac- Abbe face Radius of ness or tive Num- FocalNo. Element Curvature Distance Index ber Length S1 First 1.92 0.8011.546 56.1 4.441 S2 Lens 8.12 0.038 S3 Second 5.64 0.222 1.679 19.2−10.1615 S4 Lens 3.05 0.312 S5 Third 4.92 0.361 1.537 55.7 53.677 S6Lens 5.78 0.314 S7 Fourth 53.368601 0.351 1.679 19.2 −187.783 S8 Lens37.52 0.383 S9 Fifth −289.96 0.280 1.620 26.0 −368.835 S10 Lens 1082.570.428 S11 Sixth 4.56 0.553 1.571 37.4 14.07256 S12 Lens 10.07 0.756 S13Seventh 16.09 0.434 1.537 55.7 −5.40772 S14 Lens 2.44 0.132 S15 FilterInfinity 0.110 1.518 64.2 S16 Infinity 0.747 S17 Imaging Infinity −0.024Plane

In the fifth example, a focal length f of the optical imaging system is5.870 mm, Fno is 2.27, FOV is 75.52°, BFL is 0.965 mm, TTL is 6.197 mm,and IMG HT is 4.62 mm.

The definitions of Fno, FOV, BFL, TTL, and IMG HT are the same as in thefirst example.

In the fifth example, the first lens 510 may have a positive refractivepower, a first surface of the first lens 510 may be convex, and a secondsurface of the first lens 510 may be concave.

The second lens 520 may have a negative refractive power, a firstsurface of the second lens 520 may be convex, and a second surface ofthe second lens 520 may be concave.

The third lens 530 may have a positive refractive power, a first surfaceof the third lens 530 may be convex, and a second surface of the thirdlens 530 may be concave.

The fourth lens 540 may have a negative refractive power, a firstsurface of the fourth lens 540 may be convex in a paraxial region of thefirst surface, and a second surface of the fourth lens 540 may beconcave in a paraxial region of the second surface.

At least one inflection point may be formed on either one or both of thefirst surface and the second surface of the fourth lens 540. Forexample, the first surface of the fourth lens 540 may be convex in aparaxial region of the first surface, and may be concave in an edgeregion of the first surface. The second surface of the fourth lens 540may be concave in a paraxial region of the second surface, and may beconvex in an edge region of the second surface.

The fifth lens 550 may have a negative refractive power, a first surfaceof the fifth lens 550 may be concave, and a second surface of the fifthlens 550 may be concave.

The sixth lens 560 may have a positive refractive power, a first surfaceof the sixth lens 560 may be convex in a paraxial region of the firstsurface, and a second surface of the sixth lens 560 may be concave in aparaxial region of the second surface.

At least one inflection point may be formed on either one or both of thefirst surface and the second surface of the sixth lens 560. For example,the first surface of the sixth lens 560 may be convex in a paraxialregion of the first surface, and may be concave in an edge region of thefirst surface. The second surface of the sixth lens 560 may be concavein a paraxial region of the second surface, and may be convex in an edgeregion of the second surface.

The seventh lens 570 may have a negative refractive power, a firstsurface of the seventh lens 570 may be convex in a paraxial region ofthe first surface, and a second surface of the seventh lens 570 may beconcave in a paraxial region of the second surface.

At least one inflection point may be formed on either one or both of thefirst surface and the second surface of the seventh lens 570. Forexample, the second surface of the seventh lens 570 may be concave in aparaxial region of the second surface, and may be convex in an edgeregion of the second surface.

The surfaces of the first lens 510 to the seventh lens 570 may have theaspheric coefficients listed in Table 10 below. For example, each of anobject-side surface and an image-side surface of each of the first lens510 to the seventh lens 570 may be aspherical.

TABLE 10 S1 S2 S3 S4 S5 S6 S7 K −0.215 −0.003 7.439 3.547 0.006 0.017−0.451 A 0.003 −0.002 −0.013 −0.007 −0.011 0.003 −0.050 B 0.009 0.0570.106 −0.101 0.079 −0.244 −0.051 C −0.029 −0.264 −0.529 0.667 −0.5441.268 0.132 D 0.063 0.605 1.366 −2.189 1.803 −3.391 −0.263 E −0.078−0.810 −2.046 4.103 −3.351 5.242 0.312 F 0.059 0.659 1.857 −4.577 3.697−4.852 −0.221 G −0.026 −0.320 −1.003 3.015 −2.396 2.648 0.091 H 0.0060.085 0.297 −1.082 0.844 −0.783 −0.020 J −0.001 −0.010 −0.037 0.163−0.125 0.096 0.002 S8 S9 S10 S11 S12 S13 S14 K −0.122 0.005 0.000 −0.0050.188 0.424 −16.203 A −0.032 −0.050 −0.064 −0.046 0.005 −0.154 −0.081 B−0.140 0.002 0.001 −0.018 −0.038 0.063 0.028 C 0.343 0.007 0.021 0.0100.019 −0.015 −0.006 D −0.486 −0.010 −0.013 −0.003 −0.006 0.002 0.001 E0.416 0.006 0.004 0.001 0.001 0.000 0.000 F −0.222 −0.002 −0.001 0.0000.000 0.000 0.000 G 0.073 0.000 0.000 0.000 0.000 0.000 0.000 H −0.0130.000 0.000 0.000 0.000 0.000 0.000 J 0.001 0.000 0.000 0.000 0.0000.000 0.000

The fifth example of the optical imaging system illustrated in FIG. 9configured according to Tables 9 and 10 above may have the aberrationproperties illustrated in FIG. 10 .

Table 11 below lists values of Conditional Expressions 1 to 11 in thefirst to fifth examples.

TABLE 11 Conditional First Second Third Fourth Fifth Expression ExampleExample Example Example Example f/f2 + f/f3 −0.44 −0.49 −0.81 −0.89−0.47 v1 − v2 44.35 30.29 37.68 36.85 36.85 TTL/f 1.08 1.03 1.03 1.031.06 n2 + n3 3.36 3.31 3.37 3.36 3.22 BFL/f 0.158 0.151 0.206 0.1990.164 D1/f 0.032 0.010 0.019 0.011 0.007 R1/f 0.372 0.327 0.305 0.3050.327 TTL/(2*IMG 0.6799 0.6800 0.6798 0.6798 0.6707 HT) Fno 2.01 2.182.14 2.20 2.27 n2 + n3 + n4 4.905 4.99 5.04 5.03 4.90 |f23|/f1 2.4482.374 1.838 1.655 2.780

According to the examples described above, an optical imaging system mayhave a reduced size and an increased focal length. The increased focallength enables the optical imaging system to have a high resolution.

While this disclosure includes specific examples, it will be apparentafter an understanding of the disclosure of this application thatvarious changes in form and details may be made in these exampleswithout departing from the spirit and scope of the claims and theirequivalents. The examples described herein are to be considered in adescriptive sense only, and not for purposes of limitation. Descriptionsof features or aspects in each example are to be considered as beingapplicable to similar features or aspects in other examples. Suitableresults may be achieved if the described techniques are performed in adifferent order, and/or if components in a described system,architecture, device, or circuit are combined in a different manner,and/or replaced or supplemented by other components or theirequivalents. Therefore, the scope of the disclosure is defined not bythe detailed description, but by the claims and their equivalents, andall variations within the scope of the claims and their equivalents areto be construed as being included in the disclosure.

What is claimed is:
 1. An optical imaging system comprising: a firstlens having a positive refractive power, a second lens having a negativerefractive power, a third lens having a negative refractive power, aconvex object-side surface in a paraxial region thereof, and a concaveimage-side surface in a paraxial region thereof, a fourth lens having apositive refractive power, a fifth lens having a refractive power, asixth lens having a positive refractive power, and a seventh lens havinga negative refractive power, wherein the first through seventh lensesare sequentially disposed in ascending numerical order along an opticalaxis of the optical imaging system from an object side of the opticalimaging system toward an image side of the optical imaging system, and aconditional expression f/f2+f/f3<−0.4 is satisfied, where f is a focallength of the optical imaging system, f2 is a focal length of the secondlens, and f3 is a focal length of the third lens.
 2. The optical imagingsystem of claim 1, wherein the fifth lens has a convex object-sidesurface in a paraxial region thereof.
 3. The optical imaging system ofclaim 1, wherein the first lens has a convex object-side surface in aparaxial region thereof and a concave image-side surface in a paraxialregion thereof.
 4. The optical imaging system of claim 1, wherein thesecond lens has a convex object-side surface in a paraxial regionthereof and a concave image-side surface in a paraxial region thereof.5. The optical imaging system of claim 1, wherein the fourth lens has aconvex image-side surface in a paraxial region thereof.
 6. The opticalimaging system of claim 1, wherein the seventh lens has a concaveobject-side surface in a paraxial region thereof and a concaveimage-side surface in a paraxial region thereof.
 7. The optical imagingsystem of claim 1, wherein a conditional expression n2+n3>3.15 issatisfied, where n2 is a refractive index of the second lens, and n3 isa refractive index of the third lens.
 8. The optical imaging system ofclaim 7, wherein a conditional expression n2+n3+n4>4.85 is satisfied,where n4 is a refractive index of the fourth lens.
 9. The opticalimaging system of claim 7, wherein a conditional expression v1-v2>30 issatisfied, where v1 is an Abbe number of the first lens, and v2 is anAbbe number of the second lens.
 10. The optical imaging system of claim1, wherein a conditional expression 0.15<BFL/f<0.25 is satisfied, whereBFL is a distance along the optical axis from an image-side surface ofthe seventh lens to an imaging surface of an image sensor.
 11. Theoptical imaging system of claim 1, wherein a conditional expression0.005<D1/f<0.04 is satisfied, where D1 is a distance along the opticalaxis from an image-side surface of the first lens to an object-sidesurface of the second lens, and f is a focal length of the opticalimaging system.
 12. The optical imaging system of claim 1, wherein aconditional expression 1.4<|f23|/f1<2.8 is satisfied, where f23 is acomposite focal length of the second lens and the third lens, and f1 isa focal length of the first lens.
 13. The optical imaging system ofclaim 1, wherein a conditional expression Fno<2.3 is satisfied, whereFno is an F-number of the optical imaging system.
 14. The opticalimaging system of claim 1, wherein a refractive index of each of atleast two lenses of the first to seventh lenses is 1.67 or higher. 15.The optical imaging system of claim 1, wherein a refractive index ofeither one or both of the second lens and the third lens is 1.67 orhigher.